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Primary cilium‐dependent mechanosensing is mediated by adenylyl cyclase 6 and cyclic AMP in bone cells
Author(s) -
Kwon Ronald Y.,
Temiyasathit Sara,
Tummala Padmaja,
Quah Clarence C.,
Jacobs Christopher R.
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.09-148007
Subject(s) - cilium , adenylyl cyclase , microbiology and biotechnology , mechanotransduction , intracellular , signal transduction , intraflagellar transport , biology , extracellular , biochemistry , flagellum , gene
Primary cilia are chemosensing and mechanosensing organelles that regulate remarkably diverse processes in a variety of cells. We previously showed that primary cilia play a role in mediating mechanosensing in bone cells through an unknown mechanism that does not involve extracellular Ca 2+ ‐dependent intracellular Ca 2+ release, which has been implicated in all other cells that transduce mechanical signals via the cilium. Here, we identify a molecular mechanism linking primary cilia and bone cell mechanotransduction that involves adenylyl cyclase 6 (AC6) and cAMP. Intracellular cAMP was quantified in MLO‐Y4 cells exposed to dynamic flow, and AC6 and primary cilia were inhibited using RNA interference. When exposed to flow, cells rapidly (<2 min) and transiently decreased cAMP production in a primary cilium‐dependent manner. RT‐PCR revealed differential expression of the membrane‐bound isoforms of adenylyl cyclase, while immunostaining revealed one, AC6, preferentially localized to the cilium. Further studies showed that decreases in cAMP in response to flow were dependent on AC6 and Gd 3+ ‐sensitive channels but not intracellular Ca 2+ release and that this response mediated flow‐induced COX‐2 gene expression. The signaling events identified provide important details of a novel early mechanosensing mechanism in bone and advances our understanding of how signal transduction occurs at the primary cilium.—Kwon R. Y., Temiyasathit, S., Tummala, P., Quah, C. C., Jacobs, C. R. Primary cilium‐dependent mechanosensing is mediated by adenylyl cyclase 6 and cyclic AMP in bone cells. FASEB J . 24, 2859–2868 (2010). www.fasebj.org